This invention relates generally to rotary machines and more particularly, to methods and apparatus for assembling and operating wind turbine machines.
Generally, a wind turbine includes a rotor having multiple blades. The blades, attached to rotatable hubs on these rotors, transform mechanical wind energy into a mechanical rotational torque that drives one or more generators. The generators are generally, but not always, rotationally coupled to the rotor through a gearbox. The gearbox steps up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert the rotational mechanical energy to electrical energy, which is fed into a utility grid. Gearless direct drive wind turbine generators also exist. The rotor, generator, gearbox and other components are typically mounted within a housing, or nacelle, that is positioned on top of a base that may be a truss or tubular tower.
Some known nacelle configurations introduce substantial weight at the top of the wind turbine tower in order to facilitate support for the wind turbine components positioned within. The associated load support features of these nacelles facilitate increased weight at the top of the wind tower. The increased weight tends to increase capital and operational costs.